1. Field of the Invention
The invention relates generally to optically variable devices and, more particularly, to a system and method for mastering optically variable devices utilizing a laser beam recorder. The invention further relates to the authentication of articles, such as, for example, optical discs, by employing such a system and method, and to resultant articles.
2. Background Information
An optically variable device (OVD) is a device which creates a change or shift in appearance, such as, for example and without limitation, a change in color or shape, when observed from different angles. The evolution of the OVD stems largely from the search for a mechanism to resist counterfeiting of certain articles and products. Complexity of design, difficulty in creating the ‘master’ OVD, and difficulty in altering the original design have evolved to make OVDs a successful tool for authenticating the article or a product from a counterfeit or “pass off.”
One product which has become increasingly popular and, therefore, increasingly susceptible to counterfeiting by thieves, is the optical disc, such as, for example, compact discs (CDs) and digital versatile discs (DVDs), which are used to store data including, for example, computer software, video data such as movies, and music. To deter counterfeiting of the optical discs many methods have been proposed and used to try and authenticate them. For example, N. C. Abraham's U.S. Pat. No. 5,452,282 discloses a method of integrating holographic elements into the same layer as the data that is recorded on the optical disc. See also, N. C. Abraham's U.S. Pat. Nos. 5,533,002 and 6,160,789.
However, with the prevalence of holographic origination systems world-wide, it has now become much easier for counterfeiters to produce either real counterfeit copies, by using similar techniques to the legitimate optical disc providers, or “pass offs,” which are copies made by using simpler techniques while attempting to simulate the authentic product.
There is, therefore, room for improvement in systems and methods for mastering OVDs.
There is further room for improvement in the authentication of articles and products, such as, for example, optical discs.